Question

In a good insulator electrons are?

Answer 1

Most solid materials are classified as insulators because they offer very large resistance to the flow of electric current. Metals are classified as conductors because their outer electrons are not tightly bound, but in most materials even the outermost electrons are so tightly bound that there is essentially zero electron flow through them with ordinary voltages. Some materials are particularly good insulators and can be characterized by their high resistivities:

Resistivity (ohm m)

Glass  

1012

Mica  

9 x 1013

Quartz (fused)  

5 x 1016

This is compared to the resistivity of copper:

Resistivity (ohm m)

Copper

1.7 x 10-8

In a conductor, electric current can flow freely, in an insulator it cannot. Metals such as copper typify conductors, while most non-metallic solids are said to be good insulators, having extremely high resistance to the flow of charge through them. ... Most atoms hold on to their electrons tightly and are insulators.

Answer 2

Hello Mate here is your answer,

Non metallic solid solids are said to be good insulator. Which having extremely high resistance to the flow of charge through them. In a conductor electric current can flow freely, but in Insulator it can't.

I hope that helps you